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65 Cards in this Set
- Front
- Back
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What is minimum inhibitory concentration (MIC)?
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• minimum amount of antimicrobial agent needed to inhibit growth of bacteria
• assists in selecting appropriate antimicrobials |
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What is the difference between bacteriocidal and bacteriostatic antibiotics?
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• Cidal: antimicrobials that act by killing the microbes (ex. commonly use bacteriocidal antibiotics to treat bacterial endocarditis)
• Static: antimicrobials that inhibit microbial replication and growth |
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What is the definition of narrow, extended, and broad spectrum antibiotics?
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• Narrow Spectrum: one organism
• Extended Spectrum: various organisms (ex. gram +/-) • Broad Spectrum (ex. gram +/-, anaerobes, atypicals) |
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How are most antimicrobials excreted by the body?
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by the kidneys
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Name 2 drugs that do not require dosage modifications for patients with renal failure.
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• erythromycin
• chloramphenicol |
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What are antimicrobials that require mild dose reductions for patients with renal failure?
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• Cephalosporins
• Clindamycin • PCN • Rifampin |
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What are antimicrobials that require major dosage reductions for patients with renal failure?
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• aminoglycosides
• Vancomycin |
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What are antimicrobials that should be avoided in patients with renal failure?
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• Nitrofurantin
• Sulfonaides • tetracylcines |
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What is a major cause of bacterial resistance?
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Beta-Lactamase
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What is the most common type of Beta-lactamase enzyme?
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penicillinase
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What are complications of antimicrobials?
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• Hypersensitivity reactions (ex. allergic rxns, photosensivity, or infusion-related rxns)
• Direct Toxicity (on the site where the drug acts) • Superinfections: caused by inappropriate treatment, non-compliance, or when endogenous bacteria (the good bacteria) is killed |
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Give an example of a bacteria that appears as diplococci
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Neisseria
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Give an example of an aerobic gram-positive rod and an anaerobic gram-positive rod
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• Aerobic: Listeria
• Anaerobic: Clostridium |
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List examples of aerobic gram-positive cocci
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• Staph. Aureus
• Staph. Epidermis • Streptococcus • Strep. Pneumoniae • MRSA • Enterococcus |
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Give examples of anaerobic gram-positive cocci
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• peptococcus
• peptostreptococcus (found in the mouth) |
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List examples of aerobic gram-negative rods
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• Acinetobacter
• Citrobacter • E. Coli • Enterobacter • H. Flu • Proteus • Pseudomonas • Salmonella • Serratia • Shigella |
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Give 2 examples of anaerobic gram-negative rods
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• Bacteroides Fragilis (common in abdominal/diarrhea related illnesses)
• Bacteroides Melaninogenicus |
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List examples of gram negative cocci
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• Moraxella catarrhalis
• Neisseria gonorrhea • Neisseria meningitidis |
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List examples of atypical bacteria
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• Chlamydia pneumonia
• Chlamydia trachomatis • Legionella • Mycobacterium tuberculosis • Mycobacterium (MAC) • Mycoplasma pneumoniae |
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Give 2 examples of protozoa
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• Pneumocysitis Carinii
• Toxoplasma gondi |
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What is the drug of choice for Pneumocystis carinii?
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Bactrim
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List examples of fungi
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• Asperigillus
• Blastomyces • Candida • Cryptococcus • Histoplasma |
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Are sulfonamides bacteriocidal or bacteriostatic?
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bacteriostatic
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What is the MOA of sulfonamides?
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inhibits bacterial synthesis of folic acid
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What is the role of PABA (p-aminobenzoic acid) in the MOA of sulfonamides?
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• PABA is an essential metabolite for the synthesis of folic acid by plants and many microrganisms
• PABA is the target of many sulfonamide drugs |
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What is the role of folic acid in the body?
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• Folic acid is one of the two major single-carbon carriers of the body
• essential for DNA synthesis |
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Give examples of anatgonists to PABA
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• Sulfones (used to treat leprosy): an example of a sulfone is Dapsone which is used in HIV patients who are allergic to Bactrim
• Para-aminosalicylic acid (2nd line antitubercular agent) |
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Describe the kinetics (absorption, distribution, metabolism, elimination) of sulfonamides
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• A - very well absorbed; can be taken orally
• D - crosses blood-brain barrier; passes into all body fluids • M - metabolized by acetylation (good for the elderly) • E - acetyllated metabolites are renally filtered (does require dosage adjustment for renal insufficiency) |
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What are adverse effects of sulfonamides?
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• hypersensitivity reactions (Steven Johnson Syndrome)
• agranulocytosis • hemolytic anemia (tesdt for G6PD deficiency) • hypoglycemia • jaundice (in adults) • kernicterus |
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What are causes of resistance with sulfonamides?
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• altered enzyme (mutations)
• increased drug inactivation • increased PABA synthesis (due to overuse of sulfonamides) |
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What is the MOA of Trimethoprim?
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• inhibits formation of tetrahydrofolic acid
• inhibits dihydrofolate reductase |
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What are characteristics of Trimethoprim?
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• can be used alone or in combination with sulfas
• bacteriostatic • bacteria can develop resistance due to the drug's reduced affinity to the enzyme |
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What are adverse effects of Trimethoprim?
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Folic Acid deficiency
* often given folic acid supplementation |
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What are uses of sulfonamides?
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• Burns
• Chlamydia • Extended spetrum (gram + and gram -) • Meningococcal meningitis (drug can cross the blood-brain barrier) • Penicillin-sensitive patients • Pneumocystis carinii & Toxoplasmosis (for treatment or prophylaxis) • Pulmonary infection • Salmonella • UTI |
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What is the MOA of penicillins?
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• inhibits bacterial wall synthesis by binding and inactivating proteins in the bacterial membrane that regulates cell wall biosynthesis
• PCN binding protein catalyzes the formation of cross links in the peptidoglycan • PCN binding often causes cell lysis • inhibits transpeptidase (which contribute to cell wall strength) |
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Penicillins are ineffective for what types of organisms?
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• only effective against organisms that synthesize peptidoglycan cell wall
• not effective againsts viruses, fungi, or mycobacterium |
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What are the general types of penicllins?
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• Natural penicillins
• Antistaphylococcal penicillins • Extended spectrum penicillins • Anti-pseudomonal penicillins |
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Give examples of natural penicillins
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• Penicillin G
• Penicillin V |
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Give examples of the antistaphylococcal penicillins
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CONDOM drugs
• C - Cloxacillin • O - Oxacillin • N - Nafcillin • D - Dicloxacillin • M - Methicillin |
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Give examples of extended spectrum penicillins
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• Ampicillin OR Ampicillin + Sulfbactam (Unasyn)
• Amoxicillin OR Amoxicillin + Clavulanic Acid (Augementin) |
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Give examples of anti-pseudomonal penicillins
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• Carbecillin
• Piperacillin or Pipercillin/Tazobactam (Zosyn) • Ticarcillin OR Ticarcillin/Clavulanic (Timentin) |
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Penicillin G is effective against what types of organisms?
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• gram +/- cocci
• gram + bacilli • spirochetes |
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What are the available formulations of Penicillin G?
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PO, IM, or IV
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Why is Penicillin G, when administered IM, given with procaine?
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Penicillin G is very painful
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A single shot Benazthine Penicillin G can be used to treat what?
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gonorrhea
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The anti-staphylococcal penicillins (CONDOM drugs) are used to treat what type of bacteria?
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penicillinase producing bacteria
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True/False: Nafcillin should not be used in patients with hepatic failure
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• Nafcillin should not be used in patients with liver failure, becuase the drug is metabolized entirely by the liver.
• The correct answer is: True |
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Which CONDOM drug is the best absorbed PO agent?
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Dicloxacillin
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Which CONDOM drugs DO NOT require renal dosage adjustment?
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• Cloxacillin
• Oxacillin • Nafcillin • Dicloxacillin * Methicillin is excreted by the kidney and require dose adjustment w/ renal failure |
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Name a side effect of Nafcillin
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bone marrow suppresion
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Name a side effect of all the penicillins
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interstitial nephritis
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What structurally distinguishes amoxicillin/ampicillin from Pencillin G?
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an amino group added to the Penicillin G ring
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What is the spectrum of activity of Ampicillin & Amoxicillin?
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• extended spectrum of activity
• Gram +/- (looses some gram + coverage, used more for gram negative bacteria) |
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What bacterias are treated with Ampicillin or Amoxicillin?
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• E. Coli
• Neisseria • Proteus • Salmonella • Shigella Expanded to gram negative: Klebsiella & Hemophillus |
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What are the available formulations of Ampicillin?
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IV (preferred), but can be taken orally
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Name a side effect of Ampicillin
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diarrhea
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Ampicillin PO is a good agent for the treatment of what?
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Salmonella or shigella poisoning
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What are available formulations of Amoxicillin?
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only PO
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What are the most common anti-pseudomonal penicillins used in a hospital?
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Pipercillin & Ticarcillin
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What organisms do the anti-pseudomonal pencillins cover?
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• DOC for non-meningital pseudomonas
• covers gram-negative bacilli and pseudomonas • less effective aginst gram-positive organisms |
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What drug should be used with Pipercillin or Ticarcillin for double coverage?
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Tobramycin (aminoglycoside)
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What are side effects of Carbecillin and Ticarcillin?
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• hypokalemia
• hypernatremia (drugs have an increased sodium load) |
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Carbecillin and Ticarcillin are not good agents for patients with what disease states?
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HTN & CHF (because of the increased sodium load)
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What are adverse effects of Pencillins?
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• C. Dificile
• GI upset • Nausea/Vomiting • Rash • Steven Johnson Syndrome • Superinfection (overgrowth of fungi) * allergies are caused by haptens |
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What is beta-lactamase?
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• a common enzyme that hydrolyzes the beta-lactam ring, rendering the drug inactive
• causes resistance to pencillins |
